Fiber-containing resin substrate, device-mounting substrate and device-forming wafer, semiconductor apparatus, and method for producing semiconductor apparatus

ABSTRACT

A fiber-containing resin substrate for collectively encapsulating a semiconductor-device-mounting surface of a substrate on which semiconductor devices are mounted or a semiconductor-device-forming surface of a wafer on which a semiconductor device is formed, including a resin-impregnated fibrous base material which is obtained by impregnating a fibrous base material with a thermosetting resin and semi-curing or curing the thermosetting resin and has a linear expansion coefficient (ppm/° C.) in an X-Y direction of less than 3 ppm, and an uncured resin layer formed of an uncured thermosetting resin on one side of the resin-impregnated fibrous base material.

This application is a Divisional application of U.S. patent applicationSer. No. 14/080,319, filed Nov. 14, 2013, which claims the benefit ofpriority of Japanese Patent Application No. 2012-252884, filed on Nov.19, 2012.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an encapsulant capable of collectiveencapsulation on a wafer level, particularly to an encapsulantsubstrate, a semiconductor-device-mounting substrate and asemiconductor-device-forming wafer that are both encapsulated with theencapsulant substrate, an individual semiconductor apparatus cut fromthe semiconductor-device-mounting substrate or thesemiconductor-device-forming wafer, and a method for producing asemiconductor apparatus using the encapsulant substrate.

2. Description of the Related Art

Various methods have been proposed and studied for encapsulating, on awafer level, a semiconductor-device-mounting surface (also simplyreferred to as a device-mounting surface, hereinafter) of a substrate onwhich semiconductor devices are mounted, or asemiconductor-device-forming surface (also simply referred to as adevice-forming surface, hereinafter) of a wafer on which semiconductordevices are formed. Example of these methods include encapsulation byspin coating, encapsulation by screen printing (Patent Document 1), anduse of a composite sheet obtained by coating a film support with ahot-melt epoxy resin (Patent Documents 2 and 3).

Among these methods, the following method has been put in practical useto encapsulate the device-mounting surface of a substrate on whichsemiconductor devices are mounted (also referred to as asemiconductor-device-mounting substrate, or simply a device-mountingsubstrate, hereinafter): A film with an adhesive layer provided each onits both sides is attached to, or an adhesive is applied by spin coatingto an upper part of a metal substrate, a silicon-wafer substrate, or aglass substrate; semiconductor devices are then mounted on thedevice-mounting surface of the substrate by arranging and bonding thedevices; and the device-mounting surface is then encapsulated with aliquid epoxy resin or an epoxy molding compound by compression moldingunder a heated condition (Patent Document 4). Similarly, a method,involving encapsulating the device-forming surface with a liquid epoxyresin or an epoxy molding compound by compression molding under a heatedcondition, has been put in practical use to encapsulate thedevice-forming surface of a wafer on which semiconductor devices areformed (also referred to as a semiconductor-device-forming wafer, orsimply a device-forming wafer, hereinafter).

Such methods enable encapsulation of a wafer or a substrate, such as ametal substrate, having a small diameter, e.g., about 200 mm (8 inches)without a serious problem, whereas encapsulation of the device-mountingsurface or device-forming surface of a wafer or a substrate having alarge diameter, e.g., 300 mm (12 inches) or more according to thesemethods brings a serious problem in that the substrate or the wafer iswarped, or the wafer is damaged, owing to contraction stress of a resin,such as an epoxy resin, during curing for the encapsulation. Suchcontraction stress may disadvantageously cause some of the devices topeel away from the substrate during encapsulating the device-mountingsurface of a large-diameter substrate on a wafer level, thereby makingmass production impossible. In particular, a thin, large-diameter waferis susceptible to breaking during encapsulating the wafer.

For the purpose of avoiding these problems against a device-mountingsubstrate or a device-forming wafer, having a large diameter, it isknown to lower the contraction stress upon curing by using a resincomposition for encapsulation with a filler added thereto by about 90%by mass, or a resin composition for encapsulation with lower elasticity(Patent Documents 1, 2, and 3).

Unfortunately, such methods, for lowering the contraction stress, bringsnew problems as follows: Adding a filler by about 90% by mass to a resincomposition for encapsulation increases the viscosity of thecomposition, resulting in an increasing force exerting on semiconductordevices, mounted on the substrate when the composition is casted andmolded for the encapsulation, so that some of the semiconductor devicesare peeled away from the substrate; Using the resin composition forencapsulation with lower elasticity leads to low encapsulationperformance, such as heat resistance and humidity resistance, althoughit suppresses warping of the encapsulated device-mounting substrate ordevice-forming wafer. These conventional methods thus cannot solve theproblems fundamentally. There is therefore a need for an encapsulantthat has excellent encapsulation performance, such as heat resistanceand humidity resistance after encapsulation, and enables thedevice-mounting surface of a substrate or the device-forming surface ofa wafer to be collectively encapsulated on a wafer level without warp ofthe substrate or wafer and peeling of a semiconductor device away fromthe substrate, even when a large-diameter wafer or a large-diametersubstrate such as a metal substrate is encapsulated.

CITATION LIST Patent Literature

[Patent Document 1] Japanese Patent Application Publication No.2002-179885

[Patent Document 2] Japanese Patent Application Publication No.2009-60146

[Patent Document 3] Japanese Patent Application Publication No.2007-001266

[Patent Document 4] Japanese Unexamined Patent Application Publication(Translation of PCT Application) No. 2004-504723

SUMMARY OF THE INVENTION

The present invention has been made to solve the problems. It is anobject of the invention to provide a fiber-containing resin substratethat has a high versatility and excellent encapsulation performance,such as heat resistance and humidity resistance after encapsulation, andenables the device-mounting surface of a substrate or the device-formingsurface of a wafer to be collectively encapsulated on a wafer level,while suppressing warping of the substrate or the wafer, peeling of asemiconductor device from a substrate, and damage of a wafer,particularly even when the substrate is a large-diameter metalsubstrate, and the wafer is a large-diameter, thin wafer. Another of thepresent invention is to provide an encapsulatedsemiconductor-device-mounting substrate and an encapsulatedsemiconductor-device-forming wafer that are encapsulated with thefiber-containing resin substrate, a semiconductor apparatus cut from theencapsulated semiconductor-device-mounting substrate or the encapsulatedsemiconductor-device-mounting substrate, and a method for producing asemiconductor apparatus using the fiber-containing resin substrate.

In order to achieve the objects, the present invention provides afiber-containing resin substrate for collectively encapsulating asemiconductor-device-mounting surface of a substrate on whichsemiconductor devices are mounted or a semiconductor-device-formingsurface of a wafer on which a semiconductor device is formed, the resinsubstrate comprising a resin-impregnated fibrous base material obtainedby impregnating a fibrous base material with a thermosetting resin andsemi-curing or curing the thermosetting resin, the resin-impregnatedfibrous base material having a linear expansion coefficient (ppm/° C.)in an X-Y direction of less than 3 ppm, and an uncured resin layerformed of an uncured thermosetting resin on one side of theresin-impregnated fibrous base material.

Such a fiber-containing resin substrate can strongly suppress thecontraction stress of a resin layer during curing by theresin-impregnated fibrous base material, which has a very smallexpansion coefficient, thereby suppressing warping of the substrate orthe wafer, peeling of the semiconductor devices from the substrate, anddamage of the wafer, during collectively encapsulating thedevice-mounting surface of the substrate or the device-forming surfaceof the wafer on a wafer level, particularly even when a large-diametermetal substrate or a large-diameter wafer is encapsulated. In addition,the fiber-containing resin substrate is a very versatile and exhibitsexcellent encapsulation performance, such as heat resistance andhumidity resistance after encapsulation.

The uncured resin layer preferably has a thickness ranging from 20 μm to2,000 μm.

The thickness of 20 μm or more is sufficient to encapsulate thedevice-mounting surface of the substrate or the device-forming surfaceof the wafer and suppress filling failure, which is expected in the caseof excessively thin thickness. The thickness of 2,000 μm or less issufficient to prevent the encapsulated semiconductor-device-mountingsubstrate or the encapsulated semiconductor-device-forming wafer tobecoming excessively thick.

The uncured resin layer is preferably formed of a thermosetting resinthat is solidified at temperatures lower than 50° C. and molten attemperatures ranging from 50° C. to 150° C.

Such a fiber-containing resin substrate is such a versatile that theuncured resin layer can maintain a uniform thickness without deformationof the uncured resin layer when the fiber-containing resin substrate isstacked on a large-diameter wafer or a large substrate at lower than 50°C.

The present invention provides an encapsulatedsemiconductor-device-mounting substrate, wherein asemiconductor-device-mounting surface of a substrate on whichsemiconductor devices are mounted is covered with the uncured resinlayer of the fiber-containing resin substrate of the present invention,and the uncured resin layer is heated and cured to collectivelyencapsulate the semiconductor-device-mounting surface with thefiber-containing resin substrate.

Such an encapsulated semiconductor-device-mounting substrate isprevented from warping and being damaged, and semiconductor devicesmounted on the substrate are prevented from being peeled.

The present invention provides an encapsulatedsemiconductor-device-forming wafer, wherein asemiconductor-device-forming surface of a wafer on which a semiconductordevice is formed is covered with the uncured resin layer of thefiber-containing resin substrate of the present invention, and theuncured resin layer is heated and cured to collectively encapsulate thesemiconductor-device-forming surface with the fiber-containing resinsubstrate.

Such an encapsulated semiconductor-device-forming wafer is preventedfrom warping and being damaged.

The wafer may have a thickness ranging from 30 μm to 100 μm and adiameter of 300 mm or more.

Even when such a thin, large-diameter wafer is used, thefiber-containing resin substrate of the present invention prevents thewafer from being damaged.

Further, the present invention provides a semiconductor apparatus, cutby dicing from the encapsulated semiconductor-device-mounting substrateor the encapsulated semiconductor-device-forming wafer.

Such a semiconductor apparatus maintains high quality by being producedwith a substrate or a wafer, which is prevented from warping andencapsulated with the fiber-containing resin substrate exhibitingexcellent encapsulation performance, such as heat resistance andhumidity resistance after encapsulation.

Further, the present invention provides a method for producing asemiconductor apparatus, comprising the steps of: covering asemiconductor-device-mounting surface of a substrate on whichsemiconductor devices are mounted or a semiconductor-device-formingsurface of a wafer on which a semiconductor device is formed with theuncured resin layer of the fiber-containing resin substrate of thepresent invention; encapsulating the semiconductor-device-mountingsurface of the substrate or the semiconductor-device-forming surface ofthe wafer collectively by heating and curing the uncured resin layer toform an encapsulated semiconductor-device-mounting substrate or anencapsulated semiconductor-device-forming wafer; and cutting theencapsulated semiconductor-device-mounting substrate or the encapsulatedsemiconductor-device-forming wafer by dicing into individual pieces ofthe semiconductor apparatus.

According to such a method for producing a semiconductor apparatus, thedevice-mounting surface or the device-forming surface can be readilycovered with the uncured resin layer of the fiber-containing resinsubstrate of the present invention without a failure in filling in thecovering step. The method enables the contraction stress of the uncuredresin layer to be suppressed during curing by using theresin-impregnated fibrous base material of the of fiber-containing resinsubstrate, thereby suppressing the warping of the encapsulated substrateor wafer, peeling of the semiconductor devices from the substrate, andthe damage of the wafer, and enabling collective encapsulation of thedevice-mounting surface or the device-forming surface in theencapsulating step. The method can produce a high-quality semiconductorapparatus, because the semiconductor apparatus is cut by dicing intoindividual pieces from the encapsulated substrate or wafer, which isprevented from warping and encapsulated with the fiber-containing resinsubstrate exhibiting excellent encapsulation performance, such as heatresistance and humidity resistance after encapsulation, in the cuttingstep.

As described above, the fiber-containing resin substrate of theinvention can suppress the contraction stress of the uncured resin layerduring curing by the resin-impregnated fibrous base material, therebysuppressing warping of the substrate or the wafer, peeling of thesemiconductor devices from the substrate, and damage of the wafer,during collectively encapsulating the device-mounting surface of thesubstrate or the device-forming surface of the wafer on a wafer level,particularly even when a large-diameter metal substrate or alarge-diameter wafer is encapsulated. In addition, the fiber-containingresin substrate is a very versatile and exhibits excellent encapsulationperformance, such as heat resistance and humidity resistance afterencapsulation.

The semiconductor-device-mounting substrate and thesemiconductor-device-forming wafer, which are encapsulated with thefiber-containing resin substrate, are prevented from warping and beingdamaged, and the semiconductor devices mounted on the substrate, such asa metal substrate, are prevented from being peeled. The semiconductordevice cut from the encapsulated device-mounting substrate anddevice-forming wafer, which are prevented from warping and encapsulatedwith the fiber-containing resin substrate exhibiting excellentencapsulation performance, such as heat resistance and humidityresistance. The method can produce a high-quality semiconductorapparatus by using the fiber-containing resin substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an example of a cross-sectional view of a fiber-containingresin substrate of the invention;

FIG. 2A is an example of a cross-sectional view of asemiconductor-device-mounting substrate encapsulated with afiber-containing resin substrate of the invention;

FIG. 2B is an example of a cross-sectional view of asemiconductor-device-forming wafer encapsulated with a fiber-containingresin substrate of the invention;

FIG. 3A is an example of a cross-sectional view of a semiconductorapparatus of the invention cut from an encapsulatedsemiconductor-device-mounting substrate;

FIG. 3B is an example of a cross-sectional view of a semiconductorapparatus of the invention cut from an encapsulatedsemiconductor-device-forming wafer; and

FIG. 4 is an example of a flow-chart of a method for producing asemiconductor apparatus with a fiber-containing resin substrate of theinvention from a substrate on which semiconductor devices are mounted.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a fiber-containing resin substrate, asemiconductor-device-mounting substrate and asemiconductor-device-forming wafer that are encapsulated with thefiber-containing resin substrate, an individual semiconductor apparatuscut from the encapsulated device-mounting substrate and device-formingwafer, and a method for producing a semiconductor apparatus using thefiber-containing resin substrate of the present invention will bedescribed in detail. The present invention is not limited to them.

As described above, there is a need for a versatile encapsulant that hasexcellent encapsulation performance, such as heat resistance andhumidity resistance after encapsulation, and enables the device-mountingsurface of a substrate or the device-forming surface of a wafer to becollectively encapsulated on a wafer level without warp of the substrateand wafer, damage of the wafer, and peeling of a semiconductor devicefrom the substrate, even when a large-diameter device-mounting substratesuch as metal or a large-diameter device-forming wafer is encapsulated.

The present inventors have intensively studied to achieve the objects.As a result, the inventors contrived a fiber-containing resin substrateincluding a resin-impregnated fibrous base material that is obtained byimpregnating a fibrous base material with a thermosetting resin andsemi-curing or curing the thermosetting resin and has a linear expansioncoefficient in an X-Y direction of less than 3 ppm, and an uncured resinlayer formed of an uncured thermosetting resin on one side of theresin-impregnated fibrous base material. The resin-impregnated fibrousbase material, which has a very small expansion coefficient, suppressesthe contraction stress of a resin layer to be suppressed during curing,thereby preventing the substrate and wafer from warping, and enablingcollective encapsulation on a wafer level with excellent encapsulationperformance. Silicon, which is commonly used for a wafer, has a linearexpansion coefficient of about 3 ppm. The resin-impregnated fibrous basematerial having a linear expansion coefficient in an X-Y direction ofless than 3 ppm can surely prevent damage of a wafer, particularly athin, large-diameter wafer having a diameter of 300 m or more and athickness of 100 μm or less. The inventors thereby brought thefiber-containing resin substrate to completion.

The inventors also found the following: A semiconductor-device-mountingsubstrate and a semiconductor-device-forming wafer that are collectivelyencapsulated with the fiber-containing resin substrate of the inventionare prevented from warping and being damaged, and the semiconductordevices mounted on the substrate are prevented from being peeled. Ahigh-quality semiconductor device can be produced by cutting such adevice-mounting substrate and a device-forming wafer into individualpieces. The inventors thereby brought the device-mounting substrate, thedevice-forming wafer, and the semiconductor apparatus to completion.

The inventors also found the following: Use of the fiber-containingresin substrate of the invention enables the device-mounting surface andthe device-forming surface to be covered and collectively encapsulatedin a simple operation. A high-quality semiconductor device can beproduced by cutting into individual pieces such a device-mountingsubstrate and a device-forming wafer, encapsulated with thefiber-containing resin substrate having excellent encapsulationperformance. The inventors thereby brought the method for producing asemiconductor apparatus to completion.

<Resin-Impregnated Fibrous Base Material>

The fiber-containing resin substrate of the present invention has aresin-impregnated fibrous base material. The resin-impregnated fibrousbase material is obtained by impregnating a fibrous base material with athermosetting resin and semi-curing or curing the thermosetting resin.The resin-impregnated fibrous base material has a linear expansioncoefficient (ppm/° C.) in an X-Y direction of less than 3 ppm andthereby suppresses the contraction stresses during curing an uncuredresin layer as described below. The resin-impregnated fibrous basematerial enables prevention of warping of the substrate and the wafer,peeling of the semiconductor device from the substrate, and damage ofthe wafer, even when the substrate is a large-diameter metal substrateand the wafer is a large-diameter wafer, particularly a thin,large-diameter wafer with a diameter of 300 mm or more and a thicknessof 100 μm or less. The X-Y direction used herein means a plane directionof the resin-impregnated fibrous base material, and the linear expansioncoefficient in the X-Y direction means a linear expansion coefficientmeasured at an optional position of an X-axis and a Y-axis in such aplane direction.

[Fibrous Base Material]

Examples of a material that can be used as the fibrous base materialinclude an inorganic fiber such as a carbon fiber, a glass fiber, aquartz glass fiber, and a metal fiber, an organic fiber such as anaromatic polyamide fiber, a polyimide fiber, and a polyamideimide fiber,a silicon carbide fiber, a titanium carbide fiber, a boron fiber, and analumina fiber. Any fibers can be used according to characteristic of aproduct. The fibrous base material is preferably a glass fiber, a quartzfiber, or a carbon fiber, more preferably a glass fiber having a highinsulating property or a quartz glass fiber.

Examples of the form of the fibrous base material include sheet-shapesuch as a roving in which long fiber filament is uniformly arranged in aconstant direction, a fibrous cloth, and a non-woven fabric, and achopped strand mat. The form is not particularly limited as long as alayered body can be formed from the material.

[Thermosetting Resin]

Examples of the thermosetting resin of the resin-impregnated fibrousbase material include an epoxy resin, a silicone resin, a phenolicresin, a cyanate resin, and a mixed resin of an epoxy resin and asilicone resin, which are described below. The thermosetting resin isnot particularly limited as long as it can be generally used toencapsulate a semiconductor device.

[Method for Producing Resin-Impregnated Fibrous Base Material]

The fibrous base material may be impregnated with the thermosettingresin by either a solvent method or a hot melt method. The solventmethod involves creating a resin varnish by dissolving the thermosettingresin in an organic solvent and impregnating the fibrous base materialwith the resin varnish. The hot melt method involves heating a solidthermosetting resin to dissolving the resin and impregnating the fibrousbase material with the dissolved thermosetting resin.

The method of semi-curing the thermosetting resin impregnated into thefibrous base material may be, but not limited to, desolvation throughheating the thermosetting resin. The method of curing the thermosettingresin impregnated into the fibrous base material may be, but not limitedto, heating the thermosetting resin.

The thickness of the resin-impregnated fibrous base material afterimpregnating a fibrous base material with a thermosetting resin andsemi-curing or curing the thermosetting resin is determined by thethickness of the fibrous base material such as a fibrous cloth to beused A plurality of fibrous base materials, such as fibrous cloths, arestacked to produce a thick resin-impregnated fibrous base material.

The term “semi-curing” used in the invention represents a B-stage status(a curing intermediate of a thermosetting resin) as defined in JIS K6800 “Glossary of Terms Used in Adhesives and Adhesion”. A resin in thisstate is softened by heating and swelled by contacting a certainsolvent, but is not completely molten and dissolved.

In both cases where the thermosetting resin impregnated into a fibrousbase material is semi-cured and cured, the thickness of theresin-impregnated fibrous base material is preferably 50 μm to 1 mm, andmore preferably 50 μm to 500 μm. The resin-impregnated fibrous basematerial having a thickness of 50 μm or more can suppress itsdeformation due to thinness. The resin-impregnated fibrous base materialhaving a thickness of 1 mm or less can prevent an increase in thethickness of a semiconductor apparatus itself.

The resin-impregnated fibrous base material is important to suppresswarping of the encapsulated device-mounting surface of thedevice-mounting substrate and the encapsulated device-forming surface ofthe device-forming wafer and to reinforce the substrate on which one ormore semiconductor devices are arranged and bonded. Accordingly, theresin-impregnated fibrous base material is preferably hard and rigid.

<Uncured Resin Layer>

The fiber-containing resin substrate of the present invention has anuncured resin layer. The uncured resin layer is composed of an uncuredthermosetting resin formed on one side of the resin-impregnated fibrousbase material. The uncured resin layer serves as a resin layer forencapsulating semiconductor devices.

The uncured resin layer preferably has a thickness ranging from 20 μm to2,000 μm. The uncured resin layer having a thickness of 20 μm or morecan sufficiently encapsulate the device-mounting surface and thedevice-forming surface, and prevent a failure in filling due tothinness. The uncured resin layer having a thickness of 2,000 μm or lessprevents an excessive increase in the thickness of the encapsulateddevice-mounting substrate and device-forming wafer.

The uncured resin layer is not particularly limited, and preferablycomposed of a liquid or solid epoxy resin, a silicone resin, or a mixedresin of an epoxy resin and a silicone resin, which are generally usedfor encapsulating semiconductor devices. In particular, the uncuredresin layer preferably contains any of the epoxy resin, the siliconeresin, and the epoxy-silicone mixed resin which are solidified attemperatures lower than 50° C. and molten at temperatures ranging from50° C. to 150° C.

[Epoxy Resin]

The epoxy resin is not particularly restricted. Examples thereof includea bisphenol type epoxy resin such as a bisphenol A type epoxy resin anda bisphenol F type epoxy resin, a biphenol type epoxy resin such as a3,3′,5,5′-tetramethyl-4,4′-biphenol type epoxy resin and a 4,4′-biphenoltype epoxy resin, a novolac type epoxy resin such as a phenol novolactype epoxy resin, a cresol novolac type epoxy resin, and a bisphenol Anovolac type epoxy resin, an epoxy resin obtained by hydrogenating anaromatic ring of a naphthalene diol type epoxy resin, a trisphenylolmethane type epoxy resin, a tetrakis phenylolethane type epoxyresin, or a phenol dicyclopentadiene novolac type epoxy resin, and aknown epoxy resin that is liquid or solid at room temperature (25° C.),such as an alicyclic epoxy resin. If necessary, a predetermined amountof an epoxy resin other than those described above can be also usedtogether.

Since the uncured resin layer composed of the epoxy resin serves as theresin layer that seals the semiconductor devices, it is preferable toreduce halogen ions such as chlorine and alkali ions such as sodium asmuch as possible. When a sample of 10 g is added to 50 ml ofion-exchange water, the solution is sealed and left to stand still in anoven at 120° C. for 20 hours, and ions are extracted at 120° C. underheating, any of extracted ions is desirable to be 10 ppm or less.

A curing agent for epoxy resins can be contained in the uncured resinlayer constituted of the epoxy resin. As the curing agent, it ispossible to use, for example, a phenol novolac resin, various kinds ofamine derivatives, an acid anhydride, or a curing agent obtained bypartially ring opening an acid anhydride or an acid anhydride group tothereby generate a carboxylic acid. Among these, the phenol novolacresin is desirably used to secure reliability of the semiconductorapparatus manufactured using the sealant laminated composite accordingto the invention. In particular, it is preferable to mix the epoxy resinand the phenol novolac resin such that a mixing ratio of epoxy groupsand phenolic hydroxyl groups is 1:0.8 to 1.3.

Additionally, to promote a reaction of the epoxy resin and the curingagent, as a reaction promoter, an imidazole derivative, a phosphinederivative, an amine derivative, or a metal compound such as an organicaluminum compound may be used, for example.

Various kinds of additives may be blended in the uncured resin layerconstituted of the epoxy resin as required. For example, for the purposeof improving properties of the resin, it is possible to add and blendadditives such as various kinds of thermoplastic resins, thermoplasticelastomers, organic synthetic rubbers, silicon-based low-stress agents,waxes, and halogen trapping agents.

[Silicone Resin]

As the silicone resin, a thermosetting silicone resin and others can beused. In particular, it is desirable for the uncured resin layerconstituted of the silicone resin to contain an addition-curablesilicone resin composition. As the addition-curable silicone resincomposition, a composition having (A) an organosilicon compound having anon-conjugated double bond, (B) organohydrogenpolysiloxane, and (C) aplatinum-based catalyst as essential components is particularlypreferable. The components (A) to (C) will be described hereinafter.

Component (A): Organosilicon Compound Having Non-Conjugated Double Bond

The organosilicon compound having a non-conjugated double bond (A) mayact as a base polymer (major agent) of a silicone resin composition, andexamples of the component (A) may include a linear organopolysiloxanehaving a non-conjugated double bond such as an alkyenyl group on bothterminals of a molecular chain, represented by a general formula (1):

R¹R²R³siO—(R⁴R⁵SiO)_(a)—(R⁶R⁷SiO)_(b)—SiR¹R²R³

wherein R¹ represents a non-conjugated double bond-containing monovalenthydrocarbon group, R² to R⁷ each represent the same or differentmonovalent hydrocarbon group, and a and b represent integers satisfying0≦a≦500, 0≦b≦250, and 0≦a+b≦500.

In the general formula (1), R¹ is a non-conjugated doublebond-containing univalent hydrocarbon group, which is preferably anon-conjugated double bond-containing univalent hydrocarbon group havingan aliphatic unsaturated bond as typified preferably by a C₂ to C₈alkenyl group, particularly preferably by a C₂ to C₆ alkenyl group.

In the general formula (1), R² to R⁷ each are the same or differentunivalent hydrocarbon groups and exemplified preferably by a C₁ to C₂₀,particularly preferably C₁ to C₁₀ alkyl group, alkenyl group, arylgroup, or aralkyl group. Further, among these, R⁴ to R⁷ each are morepreferably a univalent hydrocarbon group excluding an aliphaticunsaturated bond, particularly preferably an alkyl group, an aryl group,or an aralkyl group that does not have an aliphatic unsaturated bondsuch as an alkenyl group. Furthermore, among these, R⁶ and R⁷ each arepreferably an aromatic univalent hydrocarbon group, more preferably, aC₆ to C₁₂ aryl group such as a phenyl group or a tolyl group.

In the general formula (1), a and b are integers satisfying 0≦a≦500,0≦b≦250, and 0≦a+b≦500, and a preferably satisfies 10≦a≦500, andparticularly preferably 10≦a≦250, b preferably satisfies 0≦b≦150, andparticularly preferably 0≦b≦100, and a+b preferably satisfies10≦a+b≦500, and particularly preferably 10≦a+b≦250.

The organopolysiloxane represented by the general formula (1) can beobtained by an alkali equilibration reaction between a cyclicdiorganopolysiloxane such as a cyclic diphenylpolysiloxane or a cyclicmethylphenylpolysiloxane and a disiloxane such as adiphenyltetravinyldisiloxane or a divinyltetraphenyldisiloxane, whichconstitutes a terminal group. However, in this case, polymerization thatis an irreversible reaction proceeds by a small amount of catalyst in anequilibration reaction using an alkali catalyst (particularly strongalkali such as KOH), and as a result, ring-opening polymerization alonequantitatively proceeds. A terminal blocking ratio is high. Therefore, asilanol group and a chloride component are not usually contained.

Specific examples of the organopolysiloxane represented by the generalformula (1) include as follows:

wherein k and m each represent an integer satisfying 0≦k≦500, andparticularly 5≦k≦250, 0≦m≦250, and particularly 0≦m≦100, and 0≦k+m≦500,preferably 5≦k+m≦250, and more preferably 10≦k+m≦250 and 0≦m/(k+m)≦0.5.

As the component (A), other than organopolysiloxanes having astraight-chain structure represented by the general formula (1), asrequired, also organopolysiloxanes having a three-dimensional networkstructure including a trifunctional siloxane unit, a tetrafunctionalsiloxane unit, and the like can be used. The organosilicon compoundshaving a non-conjugated double bond (A) may be used singularly or in acombination of two or more kinds thereof.

The amount of a group (monovalent hydrocarbon group having a double bondbonded to a Si atom) having a non-conjugated double bond in theorganosilicon compound having a non-conjugated double bond (A) ispreferably 1 to 50% by mole in all monovalent hydrocarbon groups (allmonovalent hydrocarbon groups bonded to Si atoms), more preferably 2 to40% by mole, and particularly preferable 5 to 30% by mole. When theamount of the group having the non-conjugated double bond is 1% by moleor more, an excellent cured material can be obtained during curing. Whenit is 50% by mole or less, mechanical characteristics thereof areexcellent during curing, and therefore this is preferable.

The organosilicon compound having a non-conjugated double bond (A)preferably have an aromatic monovalent hydrocarbon group (an aromaticmonovalent hydrocarbon group bonded to a Si atom), such as an aryl grouprepresented by a phenyl group. The content of the aromatic monovalenthydrocarbon group is preferably 0 to 95% by mole in all monovalenthydrocarbon groups (all monovalent hydrocarbon groups bonded to Siatoms), more preferably 10 to 90% by mole, and particularly preferably20 to 80% by mole. A resin containing an appropriate amount of aromaticmonovalent hydrocarbon group has an advantage of excellent mechanicalcharacteristics during curing and easy manufacturing.

Component (B): Organohydrogenpolysiloxane

The component (B) may act as a cross-linker (curing agent) for asilicone resin component. The organohydrogenpolysiloxane as thecomponent (B) is preferably an organohydrogenpolysiloxane having two ormore, particularly three or more, and still particularly about 3 toabout 100 hydrogen atoms bonded to silicon atoms (SiH groups) permolecule. The organohydrogenpolysiloxane having two or more hydrogenatoms bonded to silicon atoms (SiH groups) per molecule can act as across-linker. The SiH group in the component (B) is subjected to anaddition reaction with the non-conjugated double bond-containing groupsuch as a vinyl group or an alkenyl group in the component (A) to form acured material.

The organohydrogenpolysiloxane (B) preferably have an aromaticmonovalent hydrocarbon group, and particularly preferably an aryl groupsuch as a phenyl group. Such an organohydrogenpolysiloxane (B) having anaromatic monovalent hydrocarbon group may have a high compatibility withthe component (A). The organohydrogenpolysiloxanes (B) can be used aloneor in a mixture of two or more kinds, and for example, anorganohydrogenpolysiloxane (B) having an aromatic hydrocarbon group canbe contained as a part or whole of the component (B).

Although not restricted, examples of the organohydrogenpolysiloxanes (B)include 1,1,3,3-tetramethyldisiloxane,1,3,5,7-tetramethylcyclotetrasiloxane,tris(dimethylhydrogensiloxy)methylsilane,tris(dimethylhydrogensiloxy)phenylsilane,1-glysidoxypropyl-1,3,5,7-tetramethylcyclotetrasiloxane,1,5-glysidoxypropyl-1,3,5,7-tetramethylcyclotetrasiloxane,1-glysidoxypropyl-5-trimethoxysilylethyl-1,3,5,7-tetramethylcyclotetrasiloxane,methylhydrogenpolysiloxane having both molecular terminals capped withtrimethylsiloxy groups, a dimethylsiloxane/methylhydrogensiloxanecopolymer having both molecular terminals capped with trimethylsiloxygroups, dimethylpolysiloxane having both molecular terminals capped withdimethylhydrogensiloxy groups, a dimethylsiloxane/methylhydrogensiloxanecopolymer having both molecular terminals capped withdimethylhydrogensiloxy groups, a methylhydrogensiloxane/diphenylsiloxanecopolymer having both molecular terminals capped with trimethylsiloxygroups, a methylhydrogensiloxane/diphenylsiloxane/dimethylsiloxanecopolymer having both molecular terminals capped with trimethylsiloxygroups, a trimethoxysilane polymer, a copolymer of a (CH₃)₂HSiO_(1/2)unit and a SiO_(4/2) unit, and a copolymer of a (CH₃)₂HSiO_(1/2) unit, aSiO_(4/2) unit, and a (C₆H₅)SiO_(3/2) unit.

An organohydrogenpolysiloxane obtained by using units represented by thefollowing structures can be also used.

Examples of the organohydrogenpolysiloxane (B) may include as follows:

A molecular structure of the organohydrogensiloxane (B) may be any of aline chain structure, a cyclic structure, a branched chain structure,and a three-dimensional network structure. However, the number ofsilicon atoms per molecule (or the degree of polymerization in the caseof a polymer) is preferably two or more, more preferably 2 to 1,000, andparticularly preferably about 2 to about 300.

The amount of the organohydrogenpolysiloxane (B) to be blended ispreferably such an amount that the number of hydrogen atoms bonded tosilicon atoms (SiH group) in the component (B) per group having anon-conjugated double bond such as an alkenyl group in the component (A)is 0.7 to 3.0.

Component (C): Platinum-Based Catalyst

As the component (C), a platinum-based catalyst is used. Examples of theplatinum-based catalyst (C) include chloroplatinic acid,alcohol-modified chloroplatinic acid, and a platinum complex having achelate structure. These components can be used alone or in acombination of two or more kinds.

The amount of the platinum-based catalyst (C) to be blended may be acuring effective amount, that is, a so-called catalyst amount. It ispreferable that the amount be generally in a range of 0.1 to 500 ppm,and particularly preferably 0.5 to 100 ppm in terms of weight ofplatinum group metal per 100 parts by mass in total of the components(A) and (B).

The uncured resin layer formed of the silicone resin becomes a resinlayer for encapsulating a semiconductor device. Therefore, it ispreferable that an ion of halogen such as chlorine and an ion of alkalisuch as sodium be reduced as much as possible. In general, it isdesirable that the amount of ions be 10 ppm or less in extraction at120° C.

[Mixed Resin of Epoxy Resin and Silicone Resin]

Examples of an epoxy resin and a silicone resin contained in the mixedresin include the epoxy resins and the silicone resins described above.

Since the uncured resin layer composed of the mixed resin serves as aresin layer for encapsulating semiconductor devices, it is preferable toreduce halogen ions such as chlorine and alkali ions such as sodium asmuch as possible. In general, the amount of ions is preferably 10 ppm orless in extraction at 120° C.

[Inorganic Filler]

The uncured resin layer of the present invention can be blended with aninorganic filler. Examples of the inorganic filler to be blended includesilica such as molten silica and crystalline silica, alumina, siliconnitride, aluminum nitride, aluminosilicate, boron nitride, glass fiber,and antimony trioxide. The average particle diameter and the shape ofthe filler are not particularly limited.

In particular, the inorganic filler to be added into an uncured resinlayer composed of an epoxy resin may be subjected to surface treatmentin advance with a coupling agent, such as a silane coupling agent (e.g.,alkoxysilane containing a monovalent hydrocarbon group substituted witha functional group such as an alkenyl group, an epoxy group, a(meth)acryloxy group, a mercapto group, an amino group, and an ureidogroup, and/or a partial hydrolytic condensate thereof), and a titanatecoupling agent.

Preferable examples of such a coupling agent include epoxy functionalalkoxysilane such as γ-glycidoxypropyltrimethoxysilane,γ-glycidoxypropylmethyldiethoxysilane, andβ-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; amino functionalalkoxysilane such as N-β(aminoethyl)-γ-aminopropyltrimethoxysilane,γ-aminopropyltriethoxysilane, andN-phenyl-γ-aminopropyltrimethoxysilane; or mercapto functionalalkoxysilane such as γ-mercaptopropyltrimethoxysilane. The blendingamount of the coupling agent used for the surface treatment and a methodof the surface treatment are not particularly restricted.

The inorganic filler to be added into an uncured resin layer composed ofa silicone resin composition may also be subjected to surface treatmentin advance with the above coupling agent.

The amount of the inorganic filler to be blended is preferably 100 to1,300 parts by mass, and particularly preferably 200 to 1,000 parts bymass per 100 parts by mass in total of a resin in the epoxy resincomposition or the silicone resin composition. When the amount is equalto or more than 100 parts by mass, sufficient strength can be obtained.When it is equal to or less than 1,300 parts by mass, a reduction inflowability due to thickening can be suppressed, and a failure infilling properties caused by a reduction in flowability can be alsosuppressed. As a result, semiconductor devices formed on a wafer andsemiconductor devices arranged and mounted on a substrate can be wellencapsulated. The inorganic filler is preferably contained in a range of50 to 95% by mass, and particularly 60 to 90% by mass of the entirecomposition constituting the uncured resin layer.

<Fiber-Containing Resin Substrate>

FIG. 1 shows an example of a cross-sectional view of a fiber-containingresin substrate of the present invention. The fiber-containing resinsubstrate 10 has the resin-impregnated fibrous base material 1 and theuncured resin layer 2. As described above, the resin-impregnated fibrousbase material 1 is produced by impregnating a fibrous base material witha thermosetting resin and semi-curing or curing the thermosetting resinand has a linear expansion coefficient (ppm/° C.) in an X-Y direction ofless than 3 ppm. The uncured resin layer 2 is composed of an uncuredthermosetting resin formed on one side of the resin-impregnated fibrousbase material.

[Method for Producing Fiber-Containing Resin Substrate]

The fiber-containing resin substrate of the invention may be produced byusing a resin-impregnated fibrous base material produced by impregnatinga fibrous base material with a thermosetting resin and semi-curing thethermosetting resin. In this production, an uncured resin layer, whichis solid at 50° C. or lower, is formed by applying a thermosettingresin, such as a liquid epoxy resin or a silicone resin, to one side ofthe resin-impregnated fibrous base material through printing ordispensing under reduced pressure or vacuum and then heating the resin.

When a thermosetting epoxy resin is used as the thermosetting resinimpregnated in the fibrous base material in the above production, theuncured thermosetting resin formed on the resin-impregnated fibrous basematerial is preferably composed of an epoxy resin. When the semi-curedthermosetting resin impregnated in the fibrous base material and thethermosetting resin of the uncured resin layer are composed of the samekind of thermosetting resin, both the resins can be cured at the sametime when the device-forming surface or the device-forming surface arecollectively encapsulated. As a result, the uncured resin layeradvantageously provide a firmer encapsulation performance. Similarly,when a silicone resin is used as the thermosetting resin impregnated inthe fibrous base material, the uncured thermosetting resin is preferablycomposed of a silicone resin.

The fiber-containing resin substrate of the invention may also beproduced by using a resin-impregnated fibrous base material produced byimpregnating a fibrous base material with a thermosetting resin andcuring the thermosetting resin. In this production, the uncured resinlayer may be formed according to various methods that have beenconventionally used for an epoxy thermosetting resin or a siliconethermosetting resin, such as press molding or printing an uncuredthermosetting resin on one side of the resin-impregnated fibrous basematerial. After the formation, the uncured resin layer is preferablypost-cured commonly at a temperature of about 180° C. for 4 to 8 hours.

In addition, as another method for forming the uncured resin layerformed of the uncured thermosetting resin on one side of theresin-impregnated fibrous base material, there are a method wherein anepoxy thermosetting resin or a silicone thermosetting resin that issolid at room temperature is pressurized under heating, and a methodwherein an epoxy resin composition is liquefied by adding an appropriateamount of polar solvent such as acetone, and printed to form a thinfilm, and the solvent is removed by a process including heating underreduced pressure to uniformly form an uncured resin layer on one side ofthe resin-impregnated fibrous base material.

According to any of the methods, an uncured resin layer formed of anuncured thermosetting resin that is free of voids and volatilecomponents and has a thickness of about 20 to 2,000 μm can be formed onone side of the resin-impregnated fibrous base material.

[Semiconductor-Device-Mounting Substrate andSemiconductor-Device-Forming Wafer]

The fiber-containing resin substrate is used for collectivelyencapsulating the device-mounting surface of thesemiconductor-device-mounting substrate or the device-forming surface ofthe semiconductor-device-forming wafer. Examples of the device-mountingsubstrate include an inorganic, metal, or organic substrate 5 on whichsemiconductor devices 3 are mounted through an adhesive 4, as shown inFIG. 2A. Examples of the device-forming wafer include a wafer 7 on whichsemiconductor devices 6 are formed, as shown in FIG. 2B. Thesemiconductor-device-mounting substrate include a semiconductor devicearray in which semiconductor devices are mounted and arranged.

<Encapsulated Semiconductor-Device-Mounting Substrate and EncapsulatedSemiconductor-Device-Forming Wafer>

FIGS. 2A and 2B show examples of cross-sectional views of anencapsulated semiconductor-device-mounting substrate and an encapsulatedsemiconductor-device-forming wafer, which are encapsulated with thefiber-containing resin substrate of the present invention. In theencapsulated device-mounting substrate 11, the device-mounting surfaceof the substrate 5 on which the semiconductor devices 3 are mounted iscovered with the uncured resin layer 2 (See FIG. 1) of thefiber-containing resin substrate 10, the uncured resin layer 2 (SeeFIG. 1) is heated and cured to provide a cured resin layer 2′, and thedevice-mounting surface is collectively encapsulated with thefiber-containing resin substrate 10 (See FIG. 2A). In the encapsulateddevice-forming wafer 12, the device-forming surface of the wafer 7 onwhich the semiconductor devices 6 are formed is covered with the uncuredresin layer 2 (See FIG. 1) of the fiber-containing resin substrate 10,the uncured resin layer 2 (See FIG. 1) is heated and cured to provide acured resin layer 2′, and the device-forming surface is collectivelyencapsulated with the fiber-containing resin substrate 10 (See FIG. 2B).

Such an encapsulated device-mounting substrate and an encapsulateddevice-forming wafer are prevented from warping, and the substrateprevents the semiconductor devices from peeling. The encapsulated waferreduces its damage, even when a thin, large-diameter wafer with adiameter of 300 mm or more and a thickness ranging from 20 μm to 100 μmis used.

<Semiconductor Device>

FIGS. 3A and 3B each show an example of a semiconductor apparatus of thepresent invention. The semiconductor apparatus 13 is obtained throughcutting by dicing the encapsulated device-mounting substrate 11 (SeeFIG. 2A) or the encapsulated device-forming wafer 12 (See FIG. 2B) intoindividual pieces. The semiconductor apparatuses 13 and 14 have highquality, because the apparatuses are cutting by dicing the encapsulateddevice-mounting substrate 11 (See FIG. 2A) or the encapsulateddevice-forming wafer 12 (See FIG. 2B) into individual pieces, which isencapsulated with the fiber-containing resin substrate excellent inencapsulation performance such as heat resistance and moistureresistance, prevented from warping, and suppress peeling of thesemiconductor device 3 from the substrate. In the semiconductorapparatus 13 cut from the encapsulated device-mounting substrate 11 (SeeFIG. 2A), the semiconductor device 3 mounted on the substrate 5 throughthe adhesive 4 is encapsulated with the fiber-containing resin substrate10 including the cured resin layer 2′ and the resin-impregnated fibrousbase material 1 (See FIG. 3A). In the semiconductor apparatus 14 cutfrom the encapsulated device-forming wafer 12 (See FIG. 2B), thesemiconductor device 6 formed on the wafer 7 is encapsulated with thefiber-containing resin substrate 10 including the cured resin layer 2′and the resin-impregnated fibrous base material 1 (See FIG. 3B).

<Method for Producing Semiconductor Apparatus>

The present invention provides a method for producing a semiconductorapparatus including steps of covering the device-mounting surface of thedevice-mounting substrate or the device-forming surface of thedevice-forming wafer with the uncured resin layer of thefiber-containing resin substrate; encapsulating the device-mountingsurface or the device-forming surface collectively by heating and curingthe uncured resin layer to form the encapsulated device-mountingsubstrate or the encapsulated device-forming wafer; and cutting theencapsulated device-mounting substrate or the encapsulateddevice-forming wafer by dicing into individual pieces of thesemiconductor apparatus. The method for producing a semiconductorapparatus of the invention will be described below with reference toFIG. 4.

[Covering Step]

In the covering step of the method for producing a semiconductorapparatus (FIG. 4 at (A)), the device-mounting surface of the substrate5 on which the semiconductor devices 3 are mounted through the adhesive4, or the device-forming surface of the device-forming wafer (not shown)is covered with the uncured resin layer 2 of the fiber-containing resinsubstrate 10 having the resin-impregnated fibrous base material 1 andthe uncured resin layer 2.

[Encapsulating Step]

In the encapsulating step of the method for producing a semiconductorapparatus (FIG. 4 at (B)), the device-mounting surface of the substrate5 on which the semiconductor devices 3 are mounted or the device-formingsurface of the device-forming wafer (not shown) is collectivelyencapsulated by heating and curing the uncured resin layer 2 of thefiber-containing resin substrate 10 to form a cured resin layer 2′. As aresult, the encapsulated device-mounting substrate 11 or theencapsulated device-forming wafer (not shown) is provided.

[Cutting Step]

In the cutting step of the method for producing a semiconductorapparatus (FIG. 4 at (C) and (D)), the encapsulated device-mountingsubstrate 11 or the encapsulated device-forming wafer (not shown) is cutinto individual semiconductor apparatus 13, 14 (See FIG. 3B).

The method for producing a semiconductor apparatus will be morespecifically described below. In the covering step and the encapsulatingstep, when a vacuum lamination apparatus used in lamination of a solderresist film or various insulator films is used, covering andencapsulating without void and warp can be performed. As a laminationprocess, any process of roll lamination, diaphragm type vacuumlamination, and air-pressure lamination can be used. Among these, thevacuum lamination and the air-pressure lamination are preferably used incombination.

Here, a description will be given of an example of using a vacuumlamination apparatus manufactured by Nichigo-Morton Co., Ltd., toencapsulate a silicon wafer having a thickness of 70 μm and a diameterof 300 mm (12 inches) with a silicone resin-impregnated fibrous basematerial in which a glass cloth (fibrous base material) with a thicknessof 50 μm is impregnated with a silicone resin and a fiber-containingresin substrate having an uncured resin layer formed of an uncuredthermosetting silicone resin having a thickness of 50 μm on one side.

Of plates that have upper and lower built-in heaters and are set to 150°C., the upper plate has a diaphragm rubber closely attached to theheater under reduced pressure. A silicon wafer having a diameter of 300mm (12 inches) is set on the lower plate, and the fiber-containing resinsubstrate is set on one side of this silicon wafer so that the uncuredresin layer surface is fit into the semiconductor-device-forming surfaceof the silicon wafer. After then, the lower plate is moved up, the upperand lower plates are closely attached to each other to form a vacuumchamber by an O-ring installed so as to surround the silicon wafer seton the lower plate, and the pressure in the vacuum chamber is reduced.When the pressure in the vacuum chamber is sufficiently reduced, a valveof a pipe connecting a vacuum pump with a space between the diaphragmrubber of the upper plate and the heater is closed to send compressedair. As a result, the upper diaphragm rubber inflates to sandwich thesilicon wafer and the fiber-containing resin substrate between the upperdiaphragm rubber and the lower plate, and vacuum lamination and curingof the resin layer formed of the thermosetting silicone resinsimultaneously progress. Thus, encapsulating is completed. A curing timeof about 3 to 20 minutes is sufficient. After the vacuum lamination iscompleted, the pressure in the vacuum chamber is restored to normalpressure, the lower plate is moved down, and the encapsulated siliconwafer is taken out. The wafer can be encapsulated without void or warpby the above-described process. When the taken silicon wafer is usuallypost-cured at a temperature of 150 to 180° C. for 1 to 4 hours,electrical characteristics or mechanical characteristics can bestabilized.

The covering and encapsulating steps using the vacuum laminationapparatus are not restricted to use of the illustrated silicone resin,and they can be also used for the epoxy resin or a mixed resin of epoxyand silicone.

According to such a method for producing a semiconductor apparatus, thesemiconductor-device-mounting surface or thesemiconductor-device-forming surface can be simply covered with theuncured resin layer of the fiber-containing resin substrate of without afailure in filling in the covering step. Further, since thefiber-containing resin substrate is used, the resin-impregnated fibrousbase material can suppress the contraction stress of the uncured resinlayer during curing. The device-mounting surface or the device-formingsurface can therefore be collectively encapsulated in the encapsulatingstep. Even when a thin large-diameter wafer or a large-diametersubstrate made of metal or the like is encapsulated, the encapsulatedsemiconductor-device-mounting substrate or the encapsulatedsemiconductor-device-forming wafer which suppresses warping of thesubstrate or the wafer and peeling of the semiconductor device from thesubstrate can be obtained. Furthermore, in the dicing step, theencapsulated device-mounting substrate or the encapsulateddevice-forming wafer which is encapsulated with the fiber-containingresin substrate excellent in encapsulation performance such as heatresistance and humidity resistance and suppresses warping can be dicedinto individual pieces. Thus, the method is a method capable ofproducing a high-quality semiconductor apparatus.

EXAMPLES

Hereinafter, the present invention will be more specifically describedwith reference to Examples and Comparative Examples, but the presentinvention is not limited to these Examples.

Example 1 Production of Resin-Impregnated Fibrous Base Material

With a planetary mixer, 60 parts by mass of cresol novolak type epoxyresin (EOCN1020, available from Nippon Kayaku Co., Ltd.) and 30 parts bymass of phenol novolak resin (H-4, available from Gun Ei ChemicalIndustry Co., Ltd.) were dissolved in 400 parts by weight of methylethyl ketone (MEK), and then 700 parts by mass of spherical silica(available from Tatsumori Ltd., average particle size: 7 μm), 0.6 partsby mass of imidazole catalyst (2E4MZ, available from Shikoku ChemicalsCorporation), and 0.5 parts by mass of silane coupling agent (KBM403,available from Shin-Etsu Chemical Co., Ltd.) were added thereto, and theresultant mixture was sufficiently stirred to obtain a dispersion ofepoxy resin composition in MEK.

A quartz glass cloth (available from Shin-Etsu Quartz Products Co.,Ltd., thickness: 50 μm) as a fibrous base material was immersed in thedispersion of epoxy resin composition in MEK, to impregnate the glasscloth with the MEK dispersion. The glass cloth was left at 60° C. for 2hours to volatilize MEK. After the volatilization of MEK, a solidcoating film was formed at room temperature (25° C.) on both faces ofthe quartz glass cloth. The glass cloth was molded under pressure at150° C. for 10 minutes with a hot press machine to obtain a moldedproduct. The product was secondarily cured at 150° C. for 1 hour, toobtain a resin-impregnated fibrous base material (I-a-1) in which animpregnated thermosetting resin was cured. The linear expansioncoefficient (ppm/° C.) in the X-Y direction of the resin-impregnatedfibrous base material was 2 ppm.

The glass cloth was impregnated with the MEK dispersion, and left at 60°C. for 2 hours to volatilize MEK. The impregnated thermosetting resinwas semi-cured to obtain a resin-impregnated fibrous base material(I-a-2). After the volatilization of DMF, a solid coating film wasformed at room temperature (25° C.) on both faces of the quartz glasscloth.

[Production of Composition for Forming Uncured Resin Layer Formed ofUncured Thermosetting Resin]

With a high-speed mixer, 60 parts by mass of cresol novolak type epoxyresin (EOCN1020, available from Nippon Kayaku Co., Ltd.), 30 parts bymass of phenol novolak resin (H-4, available from Gun Ei ChemicalIndustry Co., Ltd.), 400 parts by mass of spherical silica (availablefrom Tatumori Ltd., average particle size: 7 μm), 0.2 parts by mass ofcatalyst TPP (triphenylphosphine, available from Hokko Chemical IndustryCo., Ltd.), and 0.5 parts by mass of silane coupling agent (KBM403,available from Shin-Etsu Chemical Co., Ltd.) were sufficiently mixed.The resultant mixture was heated and kneaded with a continuous kneader,then formed into a sheet, and cooled. The sheet was pulverized and anepoxy resin composition (I-b) was obtained as a granular powder.

[Production of Fiber-Containing Resin Substrate]

The semi-cured epoxy resin-impregnated fibrous base material (I-a-2) wasset on a lower mold of a compression molding machine capable of heatingand pressurizing under reduced pressure, and a granular powder of theepoxy resin composition (I-b) was uniformly dispersed on the basematerial. The temperature of upper and lower molds was set to 80° C., afluororesin-coated PET film (release film) was set on the upper mold,and the inside pressure of the mold was reduced to a vacuum level.Compression molding was performed for 3 minutes so that a resinthickness was 80 μm to produce a fiber-containing resin substrate (I-c).After molding, the substrate was cut into a disc having a diameter of300 mm (12 inches).

[Covering and Encapsulating of Wafer on which Semiconductor Device isFormed]

Next, a vacuum lamination apparatus (manufactured by Nichigo-Morton Co.,Ltd.) of which a plate temperature was set to 130° C. was used toperform covering and encapsulating. First, a silicon wafer having adiameter of 300 mm (12 inches) and a thickness of 70 μm was set on alower plate, and covered with the epoxy resin composition (I-b) surfacethat was an uncured resin layer of the fiber-containing resin substrate(I-c) from which the release film was removed so that the compositionsurface was fitted to a silicon wafer surface. The plate was then closedand vacuum compression molding was performed for 5 minutes to cure andencapsulate. After curing and encapsulating, a silicon wafer that wasencapsulated with the fiber-containing resin substrate (I-c) was furtherpost-cured at 150° C. for 2 hours, to obtain an encapsulatedsemiconductor-device-forming wafer (I-d).

Example 2

With a high-speed mixer, 60 parts by mass of cresol novolak type epoxyresin (EOCN1020, available from Nippon Kayaku Co., Ltd.), 30 parts bymass of phenol novolak resin (H-4, available from Gun Ei ChemicalIndustry Co., Ltd.), 300 parts by mass of spherical silica (availablefrom Tatumori Ltd., average particle size: 7 μm), 0.2 parts by mass ofcatalyst TPP (triphenylphosphine, available from Hokko Chemical IndustryCo., Ltd.), and 0.5 parts by mass of silane coupling agent (KBM403,available from Shin-Etsu Chemical Co., Ltd.) were sufficiently mixed.The resultant mixture was heated and kneaded with a continuous kneader,then formed into a sheet, and cooled. The sheet was pulverized to obtainan epoxy resin composition (II-b) as a granular powder.

[Production of Fiber-Containing Resin Substrate]

The semi-cured epoxy resin-impregnated fibrous base material (II-a)produced in the same manner as in Example 1 was set on a lower mold of acompression molding machine capable of heating and pressurizing underreduced pressure, and a granular powder of the epoxy resin composition(II-b) was uniformly dispersed on the base material. The temperature ofupper and lower molds was set to 80° C., a fluororesin-coated PET film(release film) was set on the upper mold, and the inside pressure of themold was reduced to a vacuum level. Compression molding was performedfor 3 minutes so that a resin thickness was 80 μm to produce afiber-containing resin substrate (II-c). After molding, the substratewas cut into a disc having a diameter of 300 mm (12 inches).

[Covering and Encapsulating of Wafer on which Semiconductor Device isFormed]

Next, a vacuum lamination apparatus (manufactured by Nichigo-Morton Co.,Ltd.) of which a plate temperature was set to 130° C. was used toperform covering and encapsulating. First, a silicon wafer having adiameter of 300 mm (12 inches) and a thickness of 70 μm was set on alower plate, and covered with the epoxy resin composition (I-b) surfacethat was an uncured resin layer of the fiber-containing resin substrate(II-c) from which the release film was removed so that the compositionsurface was fitted to a silicon wafer surface. The plate was then closedand vacuum compression molding was performed for 5 minutes to cure andencapsulate the wafer. After the curing and encapsulating, a siliconwafer encapsulated with the fiber-containing resin substrate (II-c) wasfurther post-cured at 150° C. for 2 hours, to obtain an encapsulatedsemiconductor-device-forming wafer (II-d).

Example 3 Production of Resin-Impregnated Fibrous Base Material

A bismaleimide triazine (BT) resin substrate (glass transitiontemperature: 185° C.) having a thickness of 70 μm was prepared and usedas a resin-impregnated fibrous base material (III-a). This substratecontained a fibrous base material of a glass cloth and spherical silicahaving a particle diameter of 0.3 μm to adjust its linear expansioncoefficient (x and y axes) to 2.9 ppm.

[Production of Composition for Forming Uncured Resin Layer Formed ofUncured Thermosetting Resin]

With a high-speed mixer, 60 parts by mass of cresol novolak type epoxyresin (EOCN1020, available from Nippon Kayaku Co., Ltd.), 30 parts bymass of phenol novolak resin (H-4, available from Gun Ei ChemicalIndustry Co., Ltd.), 400 parts by mass of spherical silica (availablefrom Tatumori Ltd., average particle size: 7 μm), 0.2 parts by mass ofcatalyst TPP (triphenylphosphine, available from Hokko Chemical IndustryCo., Ltd.), and 0.5 parts by mass of silane coupling agent (KBM403,available from Shin-Etsu Chemical Co., Ltd.) were sufficiently mixed.The resultant mixture was heated and kneaded with a continuous kneader,then formed into a sheet, and cooled. The sheet was pulverized to obtainan epoxy resin composition (III-b) as a granular powder.

[Production of Fiber-Containing Resin Substrate]

The epoxy resin-impregnated fibrous base material (III-a) was set on alower mold of a compression molding machine capable of heating andpressurizing under reduced pressure, and a granular powder of the epoxyresin composition (III-b) was uniformly dispersed on the base material.The temperature of upper and lower molds was set to 80° C., afluororesin-coated PET film (release film) was set on the upper mold,and the inside pressure of the mold was reduced to a vacuum level.Compression molding was performed for 3 minutes so that a resinthickness was 80 μm to produce a fiber-containing resin substrate(III-c). After molding, the substrate was cut into a disc having adiameter of 300 mm (12 inches).

[Covering and Encapsulating of Wafer on which Semiconductor Device isFormed]

Next, a vacuum lamination apparatus (manufactured by Nichigo-Morton Co.,Ltd.) of which a plate temperature was set to 170° C. was used toperform covering and encapsulating. First, a silicon wafer in which 400pieces of silicone chips (shape: 5 mm×7 mm, thickness: 100 μm) werearranged and mounted on a metal substrate having a diameter of 300 mm(12 inches) and a thickness of 100 μm through an adhesive of which theadhesion force was reduced at a high temperature was set on a lowerplate, and covered with the epoxy resin composition (III-b) surface thatwas an uncured resin layer of the fiber-containing resin substrate(III-c) from which the release film was removed so that the compositionsurface was fitted to a silicon wafer surface. The plate was then closedand vacuum compression molding was performed for 5 minutes to cure andencapsulate the wafer. After curing and encapsulating, the wafer waspost-cured at 170° C. for 4 hours, to obtain an encapsulatedsemiconductor-device-forming wafer (III-d).

Comparative Example 1 Production of Resin-Impregnated Fibrous BaseMaterial

With a planetary mixer, 60 parts by mass of cresol novolak type epoxyresin (EOCN1020, available from Nippon Kayaku Co., Ltd.) and 30 parts bymass of phenol novolak resin (H-4, available from Gun Ei ChemicalIndustry Co., Ltd.) were dissolved in 400 parts by weight of methylethyl ketone (MEK), and then 400 parts by mass of spherical silica(available from Tatsumori Ltd., average particle size: 7 μm), 0.6 partsby mass of imidazole catalyst (2E4MZ, available from Shikoku ChemicalsCorporation), and 0.5 parts by mass of silane coupling agent (KBM403,available from Shin-Etsu Chemical Co., Ltd.) were added. The resultantmixture was sufficiently stirred to obtain a dispersion of epoxy resincomposition in MEK.

A quartz glass cloth (available from Shin-Etsu Quartz Products Co.,Ltd., thickness: 50 μm) as a fibrous base material was immersed in thedispersion of epoxy resin composition in MEK, to impregnate the glasscloth with the MEK dispersion. The glass cloth was left at 60° C. for 2hours to volatilize MEK. After the volatilization of MEK, a solidcoating film was formed at room temperature (25° C.) on both faces ofthe quartz glass cloth. The glass cloth was molded under pressure at150° C. for 10 minutes with a hot press machine to obtain a moldedproduct. The product was secondarily cured at 150° C. for 1 hour, toobtain a resin-impregnated fibrous base material (IV-a) in which animpregnated thermosetting resin was cured. The linear expansioncoefficient in the X-Y direction of the epoxy resin-impregnated fibrousbase material (IV-a) was 16 ppm.

[Production of Composition for Forming Uncured Resin Layer Constitutedof Uncured Thermosetting Resin]

With a high-speed mixer, 60 parts by mass of cresol novolak type epoxyresin (EOCN1020, available from Nippon Kayaku Co., Ltd.), 30 parts bymass of phenol novolak resin (H-4, available from Gun Ei ChemicalIndustry Co., Ltd.), 400 parts by mass of spherical silica (availablefrom Tatumori Ltd., average particle size: 7 μm), 0.2 parts by mass ofcatalyst TPP (triphenylphosphine, available from Hokko Chemical IndustryCo., Ltd.), and 0.5 parts by mass of silane coupling agent (KBM403,available from Shin-Etsu Chemical Co., Ltd.) were sufficiently mixed.The resultant mixture was heated and kneaded with a continuous kneader,then formed into a sheet, and cooled. The sheet was pulverized to obtainan epoxy resin composition (IV-b) as a granular powder.

[Production of Fiber-Containing Resin Substrate]

The epoxy resin-impregnated fibrous base material (IV-a) was set on alower mold of a compression molding machine capable of heating andpressurizing under reduced pressure, and a granular powder of the epoxyresin composition (IV-b) was uniformly dispersed on the base material.The temperature of upper and lower molds was set to 80° C., afluororesin-coated PET film (release film) was set on the upper mold,and the inside pressure of the mold was reduced to a vacuum level.Compression molding was performed for 3 minutes so that a resinthickness was 80 μm to produce a fiber-containing resin substrate(IV-c). After molding, the substrate was cut into a disc having adiameter of 300 mm (12 inches).

[Covering and Encapsulating of Wafer on which Semiconductor Device isFormed]

Next, a vacuum lamination apparatus (manufactured by Nichigo-Morton Co.,Ltd.) of which a plate temperature was set to 130° C. was used toperform covering and encapsulating. First, a silicon wafer having adiameter of 300 mm (12 inches) and a thickness of 70 μm was set on alower plate, and covered with the epoxy resin composition (IV-b) surfacethat was an uncured resin layer of the fiber-containing resin substrate(IV-c) from which the release film was removed so that the compositionsurface was fitted to a silicon wafer surface. The plate was then closedand vacuum compression molding was performed for 5 minutes to cure andencapsulate the wafer. After the curing and encapsulating, a siliconwafer encapsulated with the fiber-containing resin substrate (IV-c) wasfurther post-cured at 150° C. for 2 hours, to obtain an encapsulatedsemiconductor-device-forming wafer (IV-d).

Comparative Example 2 Substrate on which Semiconductor Device is Mounted

On a metal substrate having a diameter of 300 mm (12 inches) and athickness of 500 μm, 400 pieces of silicon chips (shape: 5 mm×7 mm,thickness: 125 μm) were arranged and mounted through an adhesive ofwhich adhesion force was reduced at a high temperature.

[Covering and Encapsulating of Substrate on which Semiconductor Deviceis Mounted]

The substrate was set on a lower metal mold of a compression moldingmachine capable compression molding under reduced pressure, and agranular powder of the epoxy resin composition (V-b) fabricated in thesame manner as that of Example 3 was uniformly dispersed. Thetemperature of upper and lower metal molds was set to 170° C., afluororesin-coated PET film (release film) was set on the upper metalmold and the inside of the metal mold was depressurized to a vacuumlevel, and compression molding was performed for 3 minutes so that aresin thickness was 50 μm to cure and encapsulate. After curing andencapsulating, the substrate was post-cured at 170° C. for 4 hours, toobtain an encapsulated semiconductor-device-mounting substrate (V-d).

The encapsulated device-forming wafers (I-d) to (IV-d) and theencapsulated device-mounting substrate (V-d) in Examples 1 to 3 andComparative Examples 1 and 2 were investigated for warp, appearance, anadhesion state of the resin and the substrate, and presence or absenceof peeling of the semiconductor device from the metal substrate. Theresults are given in Table 1. The appearance was evaluated by whether avoid or an unfilled state was present or not, and determined to be goodwhen neither the void nor unfilled state were present. The adhesionstate was determined to be good when the peeling during molding was notfound.

TABLE 1 Compar- Compar- Ex- Ex- Ex- ative Ex- ative Ex- ample 1 ample 2ample 3 ample 1 ample 2 Appearance Good Good Good Good Good Warp ofsubstrate 0.8 0.9 0.5 10 8 (mm) Adhesion state Good Good Good Good GoodAppearance/void None None None None Fine void Appearance/not None NoneNone None None filling Peeling from — — — Presence Presencesubstrate/damage of wafer Heating cycle test No No No Partial Partialproblem problem problem peeling peeling Humidity resistance No No No NoNo test problem problem problem problem problem

The encapsulated device-mounting substrate and the encapsulateddevice-forming wafer in each of Examples 1 to 3 and Comparative Examples1 and 2 were cut by dicing into individual pieces, and a heat resistancetest and a humidity resistance test were performed on each semiconductorapparatus as follows: In the heat resistance test, a test piece wassubjected to a heat cycle test (the test piece was held at −25° C. for10 minutes and then held at 125° C. for 10 minutes, and this cycle wasrepeated 1,000 times). After the test, continuity was evaluated. In thehumidity resistance test, a direct voltage of 10 V was applied to bothpoles of circuit of the test piece under conditions of a temperature of85° C. and a relative humidity of 85%, and the occurrence of shortcircuit was evaluated with a migration tester (MIG-86, manufactured byIMV CORPORATION). The results revealed that the encapsulateddevice-forming wafers and the encapsulated device-mounting substrate inExamples 1 to 3 were excellent in heat resistance and humidityresistance.

The results of Comparative Examples 1 and 2, in which theresin-impregnated fibrous base material of the present invention was notused, revealed the following: In the case where the device-mountingsurface and the device-forming surface were collectively encapsulated ina manner described in each of Comparative Examples, the encapsulateddevice-forming wafer (IV-d) and the encapsulated device-mountingsubstrate (V-d) greatly warped, the wafer (IV-d) was damaged, and somesemiconductor devices were peeled from the substrate (V-d) (See Table1). In Comparative Examples 1 and 2, some semiconductor devices werepartially peeled in the heat cycle test.

On the contrary, the results of Examples 1 to 3 revealed that theencapsulated device-forming wafers (I-d) to (III-d), encapsulated withthe fiber-containing resin substrate of the present invention, greatlysuppressed its warping, were not damaged, had good appearance and goodadhesion state, and had neither void nor an unfilled state. Thus, theresin-impregnated fibrous base material of the present invention cansuppress the contraction stress during curing of the uncured resin,thereby enabling prevention of warping of a thin substrate and a thinwafer, the peeling of the semiconductor device from the substrate, andthe damage of the wafer.

It is to be noted that the present invention is not limited to theforegoing embodiment. The embodiment is just an exemplification, and anyexamples that have substantially the same feature and demonstrate thesame functions and effects as those in the technical concept describedin claims of the present invention are included in the technical scopeof the present invention.

What is claimed is:
 1. An encapsulated semiconductor-device-mountingsubstrate, wherein a semiconductor-device-mounting surface of asubstrate on which semiconductor devices are mounted is covered with anuncured resin layer of a fiber-containing resin substrate, thefiber-containing resin substrate comprising: a resin-impregnated fibrousbase material obtained by impregnating a fibrous base material with athermosetting resin and semi-curing or curing the thermosetting resin,the resin-impregnated fibrous base material having a linear expansioncoefficient in an X-Y direction of less than 3 ppm; and the uncuredresin layer that is formed of an uncured thermosetting resin on one sideof the resin-impregnated fibrous base material; and the uncured resinlayer is heated and cured to collectively encapsulate thesemiconductor-device-mounting surface with the fiber-containing resinsubstrate.
 2. The encapsulated semiconductor-device-mounting substrateaccording to claim 1, wherein the uncured resin layer has a thicknessranging from 20 μm to 2,000 μm.
 3. The encapsulatedsemiconductor-device-mounting substrate according to claim 1, whereinthe uncured resin layer is formed of a thermosetting resin that issolidified at temperatures lower than 50° C. and molten at temperaturesranging from 50° C. to 150° C.
 4. The encapsulatedsemiconductor-device-mounting substrate according to claim 2, whereinthe uncured resin layer is formed of a thermosetting resin that issolidified at temperatures lower than 50° C. and molten at temperaturesranging from 50° C. to 150° C.
 5. An encapsulatedsemiconductor-device-forming wafer, wherein asemiconductor-device-forming surface of a wafer on which a semiconductordevice is formed is covered with an uncured resin layer of afiber-containing resin substrate, the fiber-containing resin substratecomprising: a resin-impregnated fibrous base material obtained byimpregnating a fibrous base material with a thermosetting resin andsemi-curing or curing the thermosetting resin, the resin-impregnatedfibrous base material having a linear expansion coefficient in an X-Ydirection of less than 3 ppm; and the uncured resin layer that is formedof an uncured thermosetting resin on one side of the resin-impregnatedfibrous base material; and the uncured resin layer is heated and curedto collectively encapsulate the semiconductor-device-forming surfacewith the fiber-containing resin substrate.
 6. The encapsulatedsemiconductor-device-forming wafer according to claim 5, wherein theuncured resin layer has a thickness ranging from 20 μm to 2,000 μm. 7.The encapsulated semiconductor-device-forming wafer according to claim5, wherein the uncured resin layer is formed of a thermosetting resinthat is solidified at temperatures lower than 50° C. and molten attemperatures ranging from 50° C. to 150° C.
 8. The encapsulatedsemiconductor-device-forming wafer according to claim 6, wherein theuncured resin layer is formed of a thermosetting resin that issolidified at temperatures lower than 50° C. and molten at temperaturesranging from 50° C. to 150° C.
 9. The encapsulatedsemiconductor-device-forming wafer according to claim 5, wherein thewafer has a thickness ranging from 30 μm to 100 μm and a diameter of 300mm or more.
 10. The encapsulated semiconductor-device-forming waferaccording to claim 8, wherein the wafer has a thickness ranging from 30μm to 100 μm and a diameter of 300 mm or more.
 11. A semiconductorapparatus, cut by dicing from the encapsulatedsemiconductor-device-mounting substrate according to claim
 1. 12. Asemiconductor apparatus, cut by dicing from the encapsulatedsemiconductor-device-mounting substrate according to claim
 4. 13. Amethod for producing a semiconductor apparatus, the method comprisingthe steps of: covering a semiconductor-device-mounting surface of asubstrate on which semiconductor devices are mounted or asemiconductor-device-forming surface of a wafer on which a semiconductordevice is formed with an uncured resin layer of a fiber-containing resinsubstrate, the fiber-containing resin substrate comprising: aresin-impregnated fibrous base material obtained by impregnating afibrous base material with a thermosetting resin and semi-curing orcuring the thermosetting resin, the resin-impregnated fibrous basematerial having a linear expansion coefficient in an X-Y direction ofless than 3 ppm; and the uncured resin layer that is formed of anuncured thermosetting resin on one side of the resin-impregnated fibrousbase material; encapsulating the semiconductor-device-mounting surfaceof the substrate or the semiconductor-device-forming surface of thewafer collectively by heating and curing the uncured resin layer to forman encapsulated semiconductor-device-mounting substrate or anencapsulated semiconductor-device-forming wafer; and cutting theencapsulated semiconductor-device-mounting substrate or the encapsulatedsemiconductor-device-forming wafer by dicing into individual pieces ofthe semiconductor apparatus.
 14. The method for producing asemiconductor apparatus according to claim 13, wherein the uncured resinlayer has a thickness ranging from 20 μm to 2,000 μm.
 15. The method forproducing a semiconductor apparatus according to claim 13, wherein theuncured resin layer is formed of a thermosetting resin that issolidified at temperatures lower than 50° C. and molten at temperaturesranging from 50° C. to 150° C.
 16. The method for producing asemiconductor apparatus according to claim 14, wherein the uncured resinlayer is formed of a thermosetting resin that is solidified attemperatures lower than 50° C. and molten at temperatures ranging from50° C. to 150° C.
 17. A semiconductor apparatus, cut by dicing from theencapsulated semiconductor-device-forming wafer according to claim 5.18. A semiconductor apparatus, cut by dicing from the encapsulatedsemiconductor-device-forming wafer according to claim 10.